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Page 2 <br />L. J. Astemborski <br />4-3212-4-328 <br />The fume hood exhaust motor for the non -sparking fan blade assembly is <br />located outside of the exhaust air stream on the roof of the factory. The <br />separation between the dispensing point in the fume hood and the fan motor is <br />approximately 105 feet. The motor is surrounded by air at atmospheric <br />temperature and pressure. This location of the motor does not meet the <br />definition in the 1993 National Electric Code in Article 500-5 of a Class I <br />hazardous area. <br />The reference (b) memo is from the exhaust fan motor supplier. The memo <br />states that the motor in question is an ordinary open squirrel cage inductica <br />motor that has no brushes, switching mechanisms, or arc producing devices. <br />The 1993 NEC in Article 501-8(b) states specifically that these types of <br />motors are acceptable for use in Class I Division 2 locations. This leads to <br />the conclusion that the motor in question would be acceptable even if the <br />motor location was considered a Class I Division 2 area per the definition of <br />a Class I Division 2 area in Article 500-5(b) in the NEC. <br />Fire Protection Engineering concludes that the existing exhaust far motor for <br />the chemical crib fume hood is acceptable as installed. <br />Please contact the undersigned if there are any questions. <br />J. J. Hollingsworth <br />4-3212 3U-84 <br />657-9703 <br />